Mercury lamp



1929. H. NAGAOKA ET AL MERCURY LAMP Filed July 8, 1925 Patented Dec. 17, 1929 UNITED STATES HANTARO NAGAOKA, OF UENO, TOKYO,

TSUNESABURO ASADA, OF KOMAGOME, TOKYO,

AND TOSHIO MACHIDA, OF KOJIMACHI-KU, TOKYO, JAPAN, ASSIGNORS TO ZAIDA'N HOJIN RIKAGAKU KENKYUJO,

F KOMAGOME, TOKYO, JAPAN MERCURY LAMP Application filed July 8,

stant length of are maintained, easy to manu- 0 a modified type of bined B P A Q, B builds up one sul facture and to transport.

In the accompanying drawings, Fig. 1 shows a standard type of the new mercury lamp according to the invention, Fig. 2 shows the new lamp and Fig. 3 illustrates the state of the lighting part of the new lamp when it is lighted.

In hitherto known mercury lamps, mercury is generally sealed in a vacuum tube of substantially vertical arrangement and the lamp is lighted in the space filled with mercury vapour only. But in such a mercury lamp, the intensity of light is faint when the pressure of mercury vapour 1s small, while the quantity of electric current required is comparatively large According to the present invention, the new mercury lamp can be lighted under vacuum, atmospheric or any other desired pressures and aifords equal merits in each case. Also, its construction is very simple and can be manufactured with small expense.

In Figs. 1 and 2, A is a horizontal tube made of silica glass, the inner diameter of which is a few millimeter and this tube constitutes the lighting portion of the new lamp. Both ends of the tube A are provided with expanded partsi'rP and Q, to which larger horizontal arms B and B are connected, so tha e copl'i- 3 horizontal U-shaped silica glass tube COi. tuting the electrode chamber. The arms and B are provided with thick capillary parts C and Q, the inner diameter being, say, one third millimeter. These are the essential features of the invention. In the standard type of the new lamp, that is, those for use under atmospheric pressure, bulbs D and D are connected to the ends of the arms B and B. Mercury electrode body is charged in the electrode chamber of the lamp through the openings M and M of the bulbs and the lead in members E and E which can not be made into an amalgam, say, of tungsten or 1925. Serial-No. 42,286.

iron, are merely dipped into the electrodes, the openings M and M being preferably closed with plugs to prevent intrusion of dust. \Vhen, however, it is desired to use the lamp under higher or reduced pressure for special use, the free ends of the arms B and B can be united to a single bulb D and this bulb D is sealed after filling the vacant space thereof with an inert gas, say, argon, under desired pressure. In this case, the lead in members E and E of, say, tungsten, must be sealed with graded seal shown in the figure.

When using, the lighting portion A is preheated with a convenient means such as a Bunsen burner or by an electric heater, and direct current is passed. Then an electric arc is started between the ends a and b of the tube A as shown in dotted line, Fig. 3, and the inner space of the main part of the portion A and the expanded parts P and Q, at the ends of the portion A are filled with light and rays from visible to ultraviolet are emitted through the transparent wall of the tube A of silica glass.

The new merits of the mercury lamp according to the invention as compared with the hitherto known ones, are as follows:

1. Owing to horizontal arrangement of the U-shaped -tube, gravity has substantially no influence on the mercury electrode when the vapor pressure is fluctuated.

2. On account of the capillary parts C and C provided in the mercury tubes B and B, the variation of the pressure of mercury produced in the lighting portion A is automatically adjusted by their buffering action, while the expanded parts P and Q also serve to adjust the variation of the mercury vapour by aflording the vapour an ample space therefor and acting somewhat as a kind of vapour ac-.

cumulator. Therefore, the fluctuation of the electric arc is possibly avoided and a constant lighting and accordingly a constant supply of current is attained.

3. On account of the capillary parts, the new lamp can be worked under any pressure and there is no necessity of sealing the mercury in vacuum as in the known ones. because the vapour generated in the lighting portion A is prefectly sealed by means of the capillary parts. This fact also enables us to simtion being expanded to make a larger space, plity the manufacture of the lamp, as any substantlally as shown and described.

one can make it by simply filling the ready made tube with mercury. ages heretofore met in transportation of the scaled mercury lamps of vacuum type are entirely avoided. Also connection of electrodes becomes very simple, viz, it is sulticient to dip them into mercury and thus graded seal can be avoided in the standard type of the new lamp.

4. By providing the expended parts P and Q at the ends of the lighting portion A, the length of the arc can be maintained constant, because the arc is formed between the points a and b, which are the joints of the main and expanded parts of the tube A. Otherwise, there may be a tendency of causing the fluctuation in the length of the arc.

5. As the new lamp can be worked under atmospheric pressure, the efiiciency of current is promoted, because, when it is worked under pressure, the intensity of the light is increased more than it is when worked under I vacuum, and it is more stable owing to the ease of adjustment of the vapor pressure than that in the usual lamp.

Claims:

1. A mercury lamp comprising a substantially horizontal U-shaped tube in which the positive and negative lead-in-members are electrically connected with an electrode of mercury, in the midway of which the lighting portion is provided, a capillary part being i also provided between each of the lead-inmembers and the lighting portion to automatically adjust the mercury vapour in the lighting portion, the ends of the lighting portion being expanded to make a larger space, the ends of the horizontal arms of said U- shaped tube being expanded to form larger spaces for receiving lead-in-members therein, substantially as shown and described.

2. A mercury lamp comprising a substantially horizontal U-shaped tube in which the positive and negative lead in members are electrically connected with an electrode of mercury, in the midway of which the lighting portion is provided, a capillary part being also provided between each of the lead in members and the lighting portion to automatically adjust the mercury vapour in the lighting portion, substantially as shown and described... 4

3. A mercurylamp comprising a substantially horizontal U-shaped tube, in which the positive and negative lead in members are electrically connected with an electrode of mercury, in the midway of which the light in g portion is provided, a capillary part being also provided between each of the lead in members and the lighting portion, to automatically adjust the mercury vapour in the lighting portion, the ends of the lighting por- In testimony whereof we aflix our signa- HANTARO NAGAOKA. TSUNESABURO ASADA. TOSHIO MACI-IIDA.

Therefore, dznntures. 

